Method and apparatus for assigning users to use interlaces in a wireless cellular communication system

• US 20060072533A1
• Filed: 10/06/2004
• Published: 04/06/2006
• Est. Priority Date: 10/06/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Smee, John Edward, Kiran, Kiran, Bhushan, Naga, Attar, Rashid Ahmed Akbar, Hou, Jilei
• Granted Patent: US 7,881,339 B2
• Time in Patent Office: Days
• US Class Current: 370/342
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements

Abstract

Methods and apparatuses to selectively assign interlace preference factors to a plurality of user terminals to use a plurality of interlaces. These methods and apparatuses may improve capacity compared to a system that allows each user terminal to transmit data in every interlace.

Claims

1. A method comprising:

determining an interlace preference factor for a first interlace, the interlace preference factor representing a probability of a first terminal transmitting data in the first interlace to a second terminal; and

based on the interlace preference factor for the first interlace, determining whether to transmit data in the first interlace from the first terminal to the second terminal.

2. The method of claim 1, wherein the first terminal is a user terminal, and the N second terminal is a base station.

3. The method of claim 1, wherein the interlace preference factor comprises a numerical value between 0 and 1 including 0 and 1.

4. The method of claim 1, further comprising:

determining an interlace preference factor for a second interlace; and

based on the interlace preference factor for the second interlace, determining whether to transmit data in the second interlace from the first terminal to the second terminal.

5. The method of claim 1, wherein determining the interlace preference factor for the first interlace comprises receiving a message from the second terminal.

6. The method of claim 1, wherein determining the interlace preference factor for the first interlace comprises retrieving a value stored in a memory.

7. The method of claim 1, wherein determining whether to transmit data in the first interlace comprises randomly generating a number.

8. The method of claim 1, further comprising:

determining whether a time period has expired;

if the time period has not expired, continuing to transmit data in the first interlace; and

if said time period expires, determining whether to transmit data in the first interlace from the first terminal to the second terminal.

9. The method of claim 8, further comprising determining another interlace preference factor for the first interlace.

10. The method of claim 1, further comprising:

determining whether the second terminal sent an acknowledgment to indicate one or more packets were correctly decoded;

if the second terminal has not sent an acknowledgment, continuing to transmit data in the first interlace; and

if the second terminal sent an acknowledgment, determining whether to transmit data in the first interlace from the first terminal to the second terminal.

11. The method of claim 10, further comprising determining another interlace preference factor for the first interlace.

12. The method of claim 1, wherein transmitting data in the first interlace uses a Code Division Multiple Access channel.

13. A method comprising:

assigning a first interlace preference factor for a first interlace to a first user terminal;

assigning a second interlace preference factor for a second interlace to the first user terminal; and

sending a message to inform the first user terminal of the assigned first and second interlace preference factors.

14. The method of claim 13, wherein the first and second interlace preference factors each comprise a numerical value between 0 and 1.

15. The method of claim 13, further comprising receiving data in the first and second interlaces via a Code Division Multiple Access channel from at least two user terminals including the first user terminal.

16. The method of claim 13, further comprising assigning a plurality of interlace preference factors for a system with K user terminals and M interlaces such that about K/M user terminals are assigned to each interlace.

17. The method of claim 13, further comprising assigning an interlace preference factor of zero for the first interlace to at least a second user terminal such that the first user terminal is the only user terminal allowed to transmit data in the first interlace.

18. The method of claim 17, further comprising changing the interlace preference factors such that the second user terminal is the only user terminal allowed to transmit data in the first interlace.

19. The method of claim 13, further comprising performing Hybrid Automatic Repeat Request (H-ARQ) with the received signals.

20. The method of claim 13, further comprising:

changing the first interlace preference factor for the first interlace of the first user terminal; and

sending a message to inform the first user terminal of the changed first interlace preference factor.

21. The method of claim 13, further comprising:

receiving signals transmitted wirelessly from a plurality of user terminals;

determining signal-to-interference-and-noise ratios for the plurality of user terminals; and

assigning interference preference factors based on said determined signal-to-interference-and-noise ratios to the plurality of user terminals.

22. The method of claim 21, wherein at least some of the received signals comprise Code Division Multiple Access signals.

23. The method of claim 21, wherein receiving signals transmitted wirelessly comprises receiving wireless signals on a common Code Division Multiple Access channel.

24. The method of claim 21, wherein the signals comprise packets of data.

25. The method of claim 13, further comprising:

determining which user terminals among a plurality of user terminals transmit signals that interfere most with each other;

assigning interlace preference factors to the user terminals that transmit signals which interfere most with each other to use different interlaces for transmitting subsequent signals; and

sending messages to the user terminals to inform them of their assigned interlaces.

26. The method of claim 25, wherein there are L user terminals, L being an integer of at least three, the method further comprising:

among the L user terminals, determining M user terminals that transmit signals which interfere most with each other'"'"'s signals, M being an integer of at least two;

assigning interlace preference factors to the M user terminals to use M different interlaces for transmitting subsequent signals;

assigning interlace preference factors to one or more remaining non-assigned L user terminals to use interlaces which the one or more remaining non-assigned L user terminals interfere with the least; and

sending messages to the user terminals to inform them of their assigned interlaces.

27. The method of claim 26, wherein L−

M=N, if N is an integer of at least two, the method further comprises determining P user terminals among N non-assigned user terminals that transmit signals which interfere most with each other;

determining which one of the P user terminals transmits signals which interfere most with the M interlaces; and

assigning an interlace preference factor to the one of the P user terminals that transmits signals which interfere most with the M interlaces to use an interlace different from the M interlaces.

28. The method of claim 26, wherein determining M user terminals that interfere most with each other'"'"'s signals comprises:

finding a signal-to-interference-and-noise ratio gained by each user terminal by removing one other user terminal by suppressing interference from that user terminal; and

comparing the signal-to-interference-and-noise ratios.

29. The method of claim 26, the messages notify each user terminal to transmit signals on a Code Division Multiple Access channel only in designated time slots of one or more interlaces assigned to the user terminal.

30. The method of claim 25, further comprising repeating said determining and assigning for each sector of a multi-sector base station.

31. The method of claim 25, wherein each interlace comprises a sequence of time slots, the time slots of each interlace being staggered with time slots of other interlaces.

32. The method of claim 31, wherein each interlace comprises groups of staggered time slots, each group comprising a defined integer number of time slots, the integer number being at least two.

33. The method of claim 26, further comprising synchronizing transmission of Code Division Multiple Access signals by the user terminals.

34. An apparatus comprising:

a transmitter to transmit data to a remote station; and

a processor to determine an interlace preference factor for a first interlace, the interlace preference factor representing a probability of the transmitter transmitting data in the first interlace to the remote station,

based on the interlace preference factor for the first interlace, the processor is configured to determine whether the transmitter will transmit data in the first interlace from the user terminal to the base station.

35. The apparatus of claim 34, wherein the interlace preference factor comprises a numerical value between 0 and 1.

36. The apparatus of claim 34, further comprising a memory to store the interlace preference factor.

37. The apparatus of claim 34, wherein the transmitter is configured to transmit data in the first interlace using a Code Division Multiple Access channel.

43. The apparatus of claim 34, further comprising a Minimum Mean Square Error antenna array to receive the signals transmitted wirelessly from the plurality of user terminals.

44. The apparatus of claim 34, wherein the channel estimator finds a signal-to-interference-and-noise ratio gained by each user terminal by removing one other user terminal, and the processor compares the signal-to-interference-and-noise ratios.

45. The apparatus of claim 34, further comprising a demodulator to demodulate received Code Division Multiple Access signals.

38. An apparatus comprising:

a processor to assign a first interlace preference factor for a first interlace to a first user terminal and assign a second interlace preference factor for a second interlace to the first user terminal; and

a transmitter to send a message to the first user terminal indicating the assigned first and second interlace preference factors.

39. The apparatus of claim 38, wherein the first and second interlace preference factors each comprise a numerical value between 0 and 1.

40. The apparatus of claim 38, further comprising a receiver to receive data in the first and second interlaces via a Code Division Multiple Access channel from at least two user terminals including the first user terminal.

41. The apparatus of claim 38, further comprising:

a receiver to process signals transmitted wirelessly from a plurality of user terminals;

a channel estimator to estimate signal-to-interference-and-noise ratios of the received signals,

wherein the processor is configured to assign interference preference factors based on said determined signal-to-interference-and-noise ratios to the plurality of user terminals.

42. The apparatus of claim 41, wherein the processor is configured to (a) determine which user terminals transmitted signals that interfere most with each other, and (b) assign interlace preference factors to the user terminals that transmitted signals which interfere most with each other to use different interlaces for transmitting subsequent signals.

46. An apparatus comprising a processor to (a) determine which user terminals transmitted signals that interfere most with each other'"'"'s signals, and (b) assign the user terminals that transmitted signals which interfere most with each other'"'"'s signals to use different interlaces for transmitting subsequent signals.